Nonkinking ropes



July 21, 1964 c, BENK 3,141,372

NONKINKING ROPES Filed June 19, 1962 INVENTOR: CLAUS BENK ATT'YS United States Patent 3,141,372 NONKINKING ROPES Claus Benk, llsny, Allgau, Germany, assignor to Vereinigte Glanzstoi'f Fabriken Aktiengesellschaft, WuppertallElberfeld, Germany Filed June 19, 1962, Ser. No. 203,523 Qlaims priority, application Germany June 20, 1961 7 Claims. (Cl. 87-6) This invention, in general, relates to nonkinking ropes in which the core of the rope comprises a central core segment about which spirally wound other successive strands provide radially successive layers of spirally wound strands. The outermost layer, in turn, is covered by a braided mantle. The ropes of the invention are especially characterized by their nonkinking qualities. The ropes of the invention are particularly well-suited for use in mountain climbing.

There are various rope structures known, as, for example, cross-braided and spiral-braided ropes, which are nonkinking. They have, however, the considerable drawback that the material utilization-that is, the ratio of the strength of the rope to the strength of the individual strands, is very low, because of the constriction of the strands at the crossing points, especially in the spiralbraided ropes. Moreover, the latter has an undesirable initial stretch.

Further, a nonkinking core-mantle rope is known, in which a bundle of core strands running parallel in the direction of the rope axis is held together by a braided mantle. These ropes shown a very good material utilization, since the strands of the core all run in the direction of the tensile stress. In case of sudden loading, especially when the rope is bent about a rounding with a very small radius-as, for example, in the fall of a mountain climber into the rope run through a carbine clasp, but also in most cases in practice in which a rope is used-only a part of the core strands is stressed under load. The part inwardly of the curvature axis of the sharp bend in the rope does not aid in supporting the load, and the breaking strength at this point is very severely reduced. By simple stranding of the core an attempt has been made to avoid the drawback of the rope with core strands running parallel in the direction of the rope axis. The strength in case of shock load was thereby appreciably increased. As important drawbacks, however, there resulted in this rope structure a tendency toward kinking and to so-called krangeln and, furthermore, the tendency to crop formation, a deformation of the rope in which the core strands change their position, forming a permanent thickening.

By subdivision of the core containing, for example, about 60% of the amount of thread in the rope, into several layers wound in differing direction and in differing thicknesses about a stranded core, freedom from kinks was, to be sure, achieved, and thereby the tendency to krangeln completely eliminated. In case of severe bending strain on such a rope with a loosely braided mantle for high flexibility, and, in general, also especially where the mantle becomes loose by partial sliding on the core, there exists also with this rope the danger that in case of deformations of the rope at this point the core structure will become loose and be displaced, and this may lead to a reduction of the strength of the rope and, furthermore, makes possible the permanent thickening already mentioned, the so-called crop formation.

It has been found in accordance with this invention that it is possible to retain the advantages of the core-mantle rope with multi-layer core free of twisting on loading, and moreover practically entirely to eliminate the danger of local deformation of the core structure and, thereby, of crop formation, by spirally wound strand layers in the core and interweaving each individual wound layer of the rope "ice core with strands running spirally in a counter direction. The strand diameter is considerably less than that of the strands of the spirally wound layer, and the number of counter-wound strands is equal to or smaller than the number of spirally-wound strands in the winding layer in question, preferably /2 or less in number. Through the counter-wound, interwoven strands, the mantlewhich on the one hand must not be too rigid, in order to allow as high as possible flexibility and suppleness of the rope, but on the other hand must not be too loose, because otherwise crop formation is easily possible, and, furthermore, because through uncontrollable changes in the structure of the rope core in case of partial shifting of the mantle the rope strength can be seriously impairedis in part relieved of its task of holding together the strand structure of the core. The mantle, therefore, in consideration of the required flexibility of the rope, can be considerably more loose than in the rope constructions of the type hitherto known. There the danger is no longer present that the structure of the rope core, on further loosening of the mantle, e.g., by partial sliding, will reduce the strength of the rope.

The strand diameter of the counter-wound strands should amount to at most to of the strand diameter in any particular winding layer. Considerably smaller strand diameters, however, are preferably used, say in the range of to 4 of the strand diameters of the winding layer in question.

Number and thickness of the counter-wound strands are governed essentially by the purpose of use of the rope, just as are the number of layers making up the core. In order to obtain especially the high material utilization and the possibility of tension balancing between the inner and outer layers in case of severe bending, it is in every case advisable to keep the diameters and number of the counterwound strands as small as possible.

The structure of the rope according to the invention is explained with the aid of a drawing which shows as an illustrative embodiment a rope of the invention consisting of a three-layered core.

In the drawing:

The figure shows an elevation of a rope of the invention with each of its central core, core sheath windings, and mantle exposed to show their structure.

Over the central core 1 consisting of straight and parallel, spirally-wound or intertwisted strands 5 of the rope there are successively spirally-wound the two layers 2 and 3, which together form the core sheath and are formed of the side-by-side spirally-wound strands 6 and 8, respectively. Simultaneously with the spiral winding of the particular layer consisting, for example, of strands with a denier of 7500, the counter-wound strands 7 and 9, respectively, are interwoven at spaced intervals. These strands have diameters considerably smaller than that of the strands 6 or 8 forming the respective core layers. The finished rope core consisting of several layers, in this case three, is then enveloped in the usual manner with a braided mantle 4 consisting of double-braided strands 10.

The yarns forming the strands of the core, core sheath and mantle may be made from synthetic fibers such as polyamides, e.g., a nylon or poly-e-caprolactam, polyacrylonitrile, polyethylene terephthalate, etc. Polyamides are preferred for the core sheath strands. The mantle strands may be also made from yarns of natural fibers such as hemp, sisal or the like.

The core sheath must be at least one spirally-wound segment and preferably has at least two spirally-wound segments. With two segments, i.e., segments 2 and 3 of the illustrated embodiment, they preferably are spirally-wound in opposite directions of rotation. The drawing shows this arrangement with one segment being 2- wound while the other is S-wound. The cross-wound,

interwoven strands of the corresponding segments are S-wound and Z-wound, respectively. With three or more core sheath windings, both Z-wound and S-wound layers are employed in the best practice of the invention.

The invention thus provides ropes having a core structure made up of a central core of straight, spirally-wound r twisted strands surrounded by a core sheath. The core sheath comprises layer (s) of spirally-wound strands in which the outer layer at least has spiral, counterwound strands interwoven with the strands of the spirallywound strands. The former strands are of a considerably smaller diameter than the latter strands, i.e., at least Va and preferably 36 to and do not exceed in numher the number of latter strands. If there are two or more layers of said spirally-wound strands, each layer preferably is interwoven with the counter-wound strands of a size and number corresponding to that above. The outer layer of the core sheath is surrounded by a crossbraided mantle. The denier size or diameters of the strands and the fibers from which they are made may be the same of different for the central core 1, the various layers of the core sheath, and/or the mantle. Also, the number of spiral turns per foot in the spiral windings of the core sheath may be varied.

The invention is hereby claimed as follows:

1. A mountaineering rope with a nonkinking core comprising a central core made of strands of synthetic polymer yarns, a core sheath about said central core including an outer layer of spirally-wound strands made of synthetic polymer yarns, said layer having spiral, counterwound strands interwoven with said spirally-wound strands, the strand diameter of said counter-wound strands being at most one eighth of the diameter of said spirally-wound strands and the number of said counter wound strands being not greater than the number of said spirally-wound strands in said outer layer, and a mantle of braided strands surrounding said core sheath.

2. A mountaineering rope according to claim 1, characterized by the feature that the diameters of the counter-wound strands are to of the diameters of said spirally-wound strands.

3. A mountaineering rope comprising a central core of strands made of synthetic polymer yarns, a core sheath about said central core made of a plurality of layers of spirally-wound strands made of synthetic polymer yarns,

'strands being of the diameters of said spirally wound strands in said additional layer.

with which strands in each layer are interwoven counterwound, spiral strands of diameters considerably less than the diameters of the diameters of said spirallywound strands in the respective layer and numbering not more than the number of said spirally-wound strands in the respective layer, and a mantle of braided strands surrounding said core sheath. 7

4. A mountaineering rope according to claim 3, characterized by the feature that the diameters of the counterwound strands are at most A; of the diameters of said spirally-wound strands.

5. A mountaineering rope according to claim 3, characterized by the feature that the diameters of the counterwound strands are to V of the diameters of said spirally-wound strands.

6. A mountaineering rope compirsing a central core made of strands of synthetic polymer yarns, a core sheath about said central core including an outer layer of spirally-Wound strands made of synthetic polymer yarns, said layer having spiral, counter-wound strands interwoven with said spirally wound strands, the diameters of said counter-wound strands being of the diameters of said spirally-wound strands of said outer layer, and the number of said counter-wound strands being at the most /2 the number of said spirally-wound strands, and a mantle of braided strands surrounding said core sheath.

7. A mountaineering rope as claimed in claim 6 wherein said core sheath comprises at least one additional layer of spirally-wound strands positioned between said central core and said outer layer, and spiral, counterwound strands interwoven with said spirally wound strands in said additional layer, said last-mentioned counter-wound strands numbering at most /2 the number of said spirally wound strands in said additional layer and the diameters of said last-mentioned counter-wound References Cited in the file of this patent UNITED STATES PATENTS 1,439,323 Petersen Dec. 19, 1922 2,087,303 Rosch et al July 20, 1937 3,030,851 Meyer Apr. 24, 1962 3,036,490 Muller et a1. May 29, 1962 

1. A MOUNTAINEERING ROPE WITH A NONKINKING CORE COMPRISING A CENTRAL CORE MADE OF STRANDS OF SYNTHETIC POLYMER YARNS, A CORE SHEATH ABOUT SAID CENTRAL CORE INCLUDING AN OUTER LAYER OF SPIRALLY-WOUND STRANDS MADE OF SYNTHETIC POLYMER YARNS, SAID LAYER HAVING SPIRAL, COUNTERWOUND STRANDS INTERWOVEN WITH SAID SPIRALLY-WOUND STRANDS, THE STRAND DIAMETER OF SAID COUNTER-WOUND 